Lightweight Deflectometer for Compaction Quality Control

Quality assessment and control (QA/QC) of compacted pavement layers involve regular monitoring of density and moisture content during compaction. In situ density is traditionally determined using sand-cone test method. However, many recent studies have indicated that stiffness- or strength-based quality measurements are easy to determine and more reliable than the density-based quality measurements. In this study, lightweight deflectometer (LWD) is used as a quality control device to assess the quality of compacted pavement layers. As a part of this study, an extensive LWD field testing program is undertaken on the expressway along the Outer Ring Road (ORR) located in Hyderabad, India, to determine the modulus of deformation (E-LWD\) of base and surface pavement layers. E-LWD of compacted base and surface layers was found to commonly range from 37.6 to 58.6 and 89.3 to 125.7 MPa, respectively. In addition, a case study on a low-volume road is presented to demonstrate the relationship between the E-LWD and in situ density obtained from the sand-cone test. LWD is found to be simple to operate and provides quick test results on any pavement layer. Hence, the frequency of quality control tests can be increased leading to an improvement in the overall quality of compacted pavement layers.